Posted
by
samzenpuson Wednesday November 14, 2012 @11:02PM
from the greased-lightning dept.

MrSeb writes "Engineers at NC State University (NCSU) have discovered a way of boosting the throughput of busy WiFi networks by up to 700%. Perhaps most importantly, the breakthrough is purely software-based, meaning it could be rolled out to existing WiFi networks relatively easily — instantly improving the throughput and latency of the network. As wireless networking becomes ever more prevalent, you may have noticed that your home network is much faster than the WiFi network at the airport or a busy conference center. The primary reason for this is that a WiFi access point, along with every device connected to it, operates on the same wireless channel. This single-channel problem is also compounded by the fact that it isn't just one-way; the access point also needs to send data back to every connected device. To solve this problem, NC State University has devised a scheme called WiFox. In essence, WiFox is some software that runs on a WiFi access point (i.e. it's part of the firmware) and keeps track of the congestion level. If WiFox detects a backlog of data due to congestion, it kicks in and enables high-priority mode. In this mode, the access point gains complete control of the wireless network channel, allowing it to clear its backlog of data. Then, with the backlog clear, the network returns to normal. We don't have the exact details of the WiFox scheme/protocol (it's being presented at the ACM CoNEXT conference in December), but apparently it increased the throughput of a 45-device WiFi network by 700%, and reduced latency by 30-40%."

I'm guessing this works to solve temporary channel congestion issues, and not over-subscription (to which the only real solution on my opinion is to get a bigger pipe at the over-subscription point). My guess is that they keep buffers for each of the host associated with the AP, and when one of the buffers begins to get to some relative threshold they ignore the RTS frames from the other stations and allow said buffer to clear to some min point before sending a CTS to the other stations.

If all of your associated host are simultaneously trying to send data in a full-mesh (all hosts talking to all hosts), I don't see how this would alleviate spectrum congestion (and you would think in this scenario latency would go up if they are round-robin'ing the queue clearing).

Implementation details would be sweet. To me this sounds like ETS queuing/COS as seen on enterprise wired L2/L3 switches. Have to wonder if there is any RED/WRED when queues reach max size? Speculation....

The difference is that most network admins shirk from the task of responsibly implementing QoS, but they'd gladly pay a hefty licensing fee to their wireless vendors for a product with a name like WiFox that 'boosts performance' by clobbering the network instead of cleverly balancing it to perform well.

... [T]he breakthrough is purely software-based, meaning it could be rolled out to existing WiFi networks relatively easily.

This is the engineer-speak version.

Sales speak: "We can slash the R&D budget to nothing for the next 5 years by selling existing hardware with incremental improvements to the software stack, maximising our likelihood of getting a brand new Audi every six months. We should probably put a new fridge in the break room, though, so the peons don't get pissy about us shafting the consumer and not giving them a pay rise for the third year running."